What property is defined as materials' ability to conduct heat?

The property defined as a material's ability to conduct heat is thermal conductivity. This term refers to the measure of how efficiently heat can move through a material. High thermal conductivity indicates that a material is effective in transferring heat, which is crucial in applications such as insulation, cooking utensils, and heat exchangers, where controlling heat flow is important.

Thermal capacity, on the other hand, relates to the amount of heat energy required to change the temperature of a material, not how well it conducts heat. Thermal expansion refers to how materials change in size or volume in response to temperature changes. Lastly, thermal resistance measures a material's ability to resist heat flow, which is the inverse of thermal conductivity. Understanding thermal conductivity helps engineers and technicians select appropriate materials for different thermal applications.